this is not a duet

Andromeda and Milky Way Might Collide Sooner Than We Think

By Bob King

The merger of the Milky Way and Andromeda galaxy won’t happen for another 4 billion years, but the recent discovery of a massive halo of hot gas around Andromeda may mean our galaxies are already touching. University of Notre Dame astrophysicist Nicholas Lehner led a team of scientists using the Hubble Space Telescope to identify an enormous halo of hot, ionized gas at least 2 million light years in diameter surrounding the galaxy.

The Andromeda Galaxy is the largest member of a ragtag collection of some 54 galaxies, including the Milky Way, called the Local Group. With a trillion stars — twice as many as the Milky Way — it shines 25% brighter and can easily be seen with the naked eye from suburban and rural skies.

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In last week’s episode of It’s Okay To Be Smart, I talked about why the moon orbits the Earth. If you haven’t watched it yet, give it a look. I’ll wait.

There’s some pretty interesting astrophysics keeping the moon orbiting Earth and not getting gobbled up by the sun, eh. But I left one thing out of that video. The moon doesn’t really orbit the Earth. Strictly speaking, the moon and the Earth orbit each other.  

Just like the Earth exerts a gravitational force on the moon, the moon and its mass are “tugging” right back on us. As a result, the two bodies are actually orbiting a point in between, called the barycenter.

If you’ve ever watched pairs figure skating, you’ve seen this in action. When spinning through this move, called a “death spiral”, the two skaters are actually rotating around a barycenter in between their two centers of mass:

This is true of any two orbiting objects, whether it’s a pair of binary stars, a planet and its star, or a planet and its moon(s). You can think of it just like a playground see-saw, with the masses and distance between the two orbiting objects determining where the “balance” point is. 

The Earth/Moon barycenter is about 1,700 km beneath the crust:

Jupiter, despite being more than five times farther from our central star than Earth is, is so massive that its barycenter lies outside of the Sun:

The Earth-Sun barycenter, on the other hand, is effectively in the center of the sun. Our mass is just peanuts compared to that of that huge burning ball of hot gas:

When two orbiting bodies have similar masses and are relatively close to each other, it can be tough to figure out who’s orbiting whom. This is one reason that some astronomers think Pluto and its moon Charon are more of a double-dwarf-planet system:

Scientists use the see-saw physics of barycenters to study planets in distant solar systems, observing these wobbly waltzes to discover planets that we can’t see with telescopes.

The dig deeper into this cool bit of astrophysics, check out this article from my friend Chris Crockett. And cue the Dead or Alive…

Episode 8: Sisters of the Sun, Cosmos: A SpaceTime Odyssey

10 Tyson Tweets

the fucking last one

You can listen to the contents of the Voyager Golden Record here.

This picture is Fox News’ worst nightmare

A republican’s back goes out every time this is reblogged

What it might look like if Earth was destroyed by a black hole.

Holy fuck

PLEASE NO

ALRIGHT LISTEN UP FOLKS AND LISTEN WELL

EARTH, IN ITS ENTIRE LIFESPAN, WILL NOT BE SUCKED UP BY A BLACK HOLE.

BLACK HOLES DO NOT ‘SUCK’ LIKE A VACCUUM CLEANER, AND SHOULD BE COMPARED MORE TO A VENUS FLYTRAP THEN A VACCUUM CLEANER. THEY ARE NOT LIKE MAGNETS AND ALTHOUGH THEIR GRAVITY IS INTENSE, IT WILL ONLY BE INTENSE IN ITS SPECIFIED AREA AND NOT OUTSIDE OF IT.

THE ONLY WAY EARTH WOULD BE SUCKED UP BY A BLACK HOLE WOULD BE IF IT WAS IN A 10KM REACH OF ONE, BUT WE ARE VERY FAR AWAY FROM ANY BLACK HOLES AND NOT EVEN OUR MOON IS THAT CLOSE TO US SO ???????

THAT SAID, IF THE SUN WERE TO BE REPLACED BY A BLACK HOLE OF THE SAME SIZE, THE EARTH WOULDN’T STOP ORBITING. IT WOULD KEEP ORBITING AROUND IT AND EVERY OTHER PLANET IN THE SOLAR SYSTEM WILL KEEP ORBITING AROUND IT. NOTHING WILL CHANGE EXCEPT FOR THE FACT THAT IT WILL BE VERY DARK.

AND IM REALLY PISSED OFF BECAUSE THAT ISN’T EVEN A BLACK HOLE THAT’S AN IMAGE OF A FUCKING GALAXY OH MY GOD, BLACK HOLES AREN’T EVEN VISIBLE YOU CAN’T SEE BLACK HOLES. THEY HAVE NO LIGHT SO LIGHT SHOULDN’T EVEN BE EMITTING FROM THAT SHIT. I’M SO PISSED I’M SO PISSED DO YOU EVEN KNOW HOW PISSED I AM.

HONESTLY THIS ENTIRE WEBSITE IS FULL OF OBLIVIOUS IDIOTS THAT BELIEVE EVERYTHING THEY SEE ON THIS WEBSITE.

as a physics student this makes me cry

Science side of tumblr has pulled the last straw.